In the case of a fitting of the above-described type known from DE 44 36 101 A1, the wedge segments sit directly on a collar extension of the first fitting part. The static friction on account of the material pairing of steel on steel contributes to preventing running-down of (e.g., undesired pivoting of) the fitting. When the fitting is driven, the wedge segments move with the lower sliding friction around the collar extension.